In an operation that would have been similar to the Mumbai attacks of 2008, gunmen and suicide bombers would have worked in tandem to launch a series of assaults in the district.

Western diplomats, many of whom are based in Abdoun, were among the targets, Jordan’sPetra news agency reported.

The plot would have culminated in mortars being fired into the district.

Samih Maayatah, Jordan’s information minister, said that the suspected terrorists had entered the country from Syria, although all 11 are believed to be Jordanian. The group is said to have been advised by al-Qaeda explosives experts in Iraq.

The uncovering of the plot comes days after Jordanian border guards arrested two cousins of Abu Musab al Zarqawi, the Jordanian militant who led al-Qaeda’s Iraqi wing, as they entered the country from Syria.

Zarqawi, who was killed by US forces in Iraq in 2006, claimed responsibility for the hotel bombings in Amman the previous year.

Zayed Sweiti and Firas Khalailah were arrested after spending five months fighting in Syria, a Jordanian Islamist leader told the French news agency AFP last week.

It is unclear, however, if they had any links with the plot.

Jordanian officials said that the group had been under surveillance for several months after the General Intelligence Department was alerted to the plot in June.

When the arrests were made, the group was in the process of choosing suicide bombers for the attacks, they said. Machine guns, and explosive materials – including TNT – were seized during the raids.

The case had not been referred to the state security court, a military tribunal, and the suspects are not being questioned.

“They will face two charges – conspiracy to carry out terrorist acts and possession of explosives,” a judicial source was quoted as saying. If convicted, the men face the death sentence.

Mr Maayatah told a press conference in Amman: “The prisoners came across the border from Syria and were caught red-handed.”

Jordan has bolstered its border security amid fears that the violence in Syria could spill over into the Kingdom. An estimated 150 American troops are currently based 35 miles from the Syrian border, advising the Jordanian military on the Syria crisis and on how to cope with the 200,000 Syrian refugees now in Jordan.

In addition, the Jordanian government has imposed strict rules on Syrian refugees in Jordan, including heavily restricting their movement outside of the refugee camps, in a bid to prevent the country being used as a base for Syrian rebels.